Harvest either heart stones or golden flowers... Unfortunately even with lvl 10 Mining or Harvesting (Forgot the proper termonology) you can still fail often, therefore its probably suggested that you have your profession as a harvester so that you can boost your empathy each day. By increasing your empathy it allows a higher succession rate of successfully harvesting or mining a Heart stone or golden flower. Furthermore, someone who had lvl 100 empathy pointed out that he was able to find a primal essence quickly and easier due to a higher lvl of empathy, thus with that I'd strongly suggest you to go with being a harvester if you are looking for primal essence